# Thread: The speed of light constant

1. Is it possible that an explanation for the speed of light being the universal constant that it actually rips through space time if it goes faster. For example we have a rocket and as it accelerates it makes a greater depression in space time just like a planet or black hole does. But if black holes theoretically rip through space-time then if you have something travel at the speed of light their depression is so deep that once they exceed the speed of light it rips through space-time. Since photons accelerate instantaneously there could be numerous energies created that don't get seen because they rip through space-time.  2.

3. no  4. Originally Posted by aep000 For example we have a rocket and as it accelerates it makes a greater depression in space time just like a planet or black hole does.
This is not correct. The source of gravity is the energy-momentum tensor, which, owing to its tensorial character, is the same for all observers. You can't somehow "increase" the gravity of an object simply by putting it into relative motion.  5. Originally Posted by Markus Hanke  Originally Posted by aep000 For example we have a rocket and as it accelerates it makes a greater depression in space time just like a planet or black hole does.
This is not correct. The source of gravity is the energy-momentum tensor, which, owing to its tensorial character, is the same for all observers. You can't somehow "increase" the gravity of an object simply by putting it into relative motion.
I think i understand where this idea comes from. Has to do with speed and mass. The faster it goes, the heavier it becomes. And it has an effect on its gravity because the mass increases. However it is not as easy as that.

I'll give a nice example. Say you put a flashlight on a rocket, you put on the flashlight, and give the rocket a relative speed. So what speed does the light become when it exited the flashlight on front of the rocket;
1)- Lightspeed in vacuum..
2)- Lightspeed in vacuum + speed of the rocket.. Which would have an effect on the "mass" and the effect gravity has on this light.  6. Originally Posted by Zwolver The faster it goes, the heavier it becomes.
Which is also wrong. This goes back to the very inappropriately named concept of "relativistic mass"; this depends on relative velocity, however, despite the name it is not actually mass at all, but merely a measure of an object's total energy. The gravitating ( rest ) mass of an object is an invariant, and the same for all observers - it doesn't increase with speed. Having said that, as I pointed out earlier, even rest mass is not the sole source of gravity; the real source is a geometric object called the energy-momentum tensor, which contains other terms as well.

So what speed does the light become when it exited the flashlight on front of the rocket
Like rest mass, the speed of light is also an invariant; all observers measure the same speed of light, irrespective of the emitter's state of relative motion.

Indeed   general relativity 